350B Stalled. Fuel Issue?

[Kaiverol]

Not sure where the vent tube is. I did try with the cap loose, to no avail. I was reading about leaving the primer lever in the down position. I’m sure I did that but I will double check. Should I try bleed at the injector pump? And is it worth checking the electric stop solenoid for voltage?

Thanks everyone, so far.

[Stan Disbrow]

Hi,

The hiss from your cap is as unwelcome as from a Copperhead coiled up on your seat. Guess how I know that?

This will help:

viewtopic.php?f=2&t=13107

Lots of nice pics. Run a wire thru that tube. The tube which runs from the bottom there all the way to just under the cap. The tube bugs love to plug up.

Stan

[Jim B]

Good point from Bruce, check the vent as pointed out. Stan's write up covers it very well.

It won't hurt to hook up a test light to the pump terminal that powers the fuel solenoid. Mount it where you can see it while running to monitor it to see if it drops out intermittently. Also check the other terminal on the top of the pump. Many have a ground strap run from that terminal to a screw on the pump, to ground the solenoid. I have known of those breaking or otherwise getting damaged, causing the solenoid to drop out intermittently.

You might carefully remove the timing window on the side of the injection pump and see if you spot any pieces that look like mouse turds behind it. It is messy, but you can also try running it with the two screws for the timing window cracked loose to allow some fuel to leak out while running. Also remove the return fitting from the Injection pump. That first fitting has a check valve in it and if pieces have plugged that it can act as you describe. Letting the fuel leak out the window prevents back pressure build up in the injection pump (caused by a plugged check valve or return line) and allows the high pressure side to work. If it stays running with the window loose it is an indication the pellethane ring in the pump is breaking up and the Injection pump needs an overhaul.

[Kaiverol]

This is great info. Pretty sure my vent tube is plugged, but because I did loosen the cap, that is probably not the main problem. I also don’t have a strainer.

I will focus on the injector pump and do the tests as given. Heading out this morning so will let you know how it goes. If IP is bad, then will discuss removal.

[Kaiverol]

Success again. This time I’m sure the problem has been found. Did all the tests, I.e. saw voltage at the stop solenoid when key on and cranking. Open screws to timing window and saw some improvement. Couldn’t keep it running real well but certainly made a difference. Decided to loosen the return fuel line and ever so slight improvement. However not a lot of fuel coming out. Then took the check valve out (new to me, but knew it had to be more than a fitting). What I found was a clear plastic piece inside that I would assume was the check valve. I put the return line on and she fired up and stayed running. Went out and worked the 350 for 45 minutes.

Looked at the vent tube earlier as well and pushed a wire inside. Wire would only go about 3/4 down into the tank and was dry. Not sure how the vent tube should work.

[Jim B]

Your tests on the pump, and the plastic piece in the check valve, indicate a pump rebuild is in order, to me. Sounds like the pellethane ring is breaking up. So was it the actual check ball you took out or a loose piece? It should have a working check valve at that location.

If you can see the outside bottom of the tank you will see weld location where the bottom of the tube is, it goes all the way down through the tank. I used a 1/16" filler wire as is used for TIG or acetylene welding to run down through my 450E's vent, because it is stiffer than regular wire. It is not a straight run and the TIG wire doesn't push easy, at least it doesn't in mine.

[Kaiverol]

I looked closer and it appears to be a glass ball and I can’t remove it. It moves a bit like against a spring. So that is the check ball. I will need to get a new check valve for it and see how it works.
I will look at the vent tube more and look for the weld and get a better wire. I did see that the tube takes a bend. Thanks.

[Kaiverol]

Haven’t had time to use machine lately, but replaced the check valve with a new one. Started machine and ran smooth. Will use a bit this week to confirm. Also replaced one bad bleed screw. Sure spins on nice when your careful with the threads. New one has an actual oring, whereas the old one had a very thin papery gasket.